There has recently been developed a plural layer coating structure which may be applied to the outside surface of a sidewall in a liquid container to bring about rapid self-healing of a puncture wound in that sidewall. That development has been found to offer significant utility in sealing puncture wounds in a container holding combustible petrochemical fuel liquid. The term “container” is used to refer to any structure which holds such a liquid, such a vehicle gas tank, a large depot storage tank, a pipeline, and others. For background purposes, reference is here made to U.S. Pat. No. 7,169,452 —a patent whose underlying application, U.S. patent application Ser. No. 11/067,525, filed Feb. 25, 2005, for “Projectile Barrier and Method”, was copending at the time of filing the present application. The basic structure of such a protective coating, which preferably is a three-layer coating, is quite fully described and illustrated in that regular patent application, and as was just mentioned, reference is made to that application to provide the reader with relevant background information.
The present invention addresses the recognition that container-stored liquid has associated with it what is known as head pressure which typically varies linearly and with an increasing value progressing downwardly from the surface of a contained liquid. Further recognizing that a puncture wound at a particular elevation in the sidewall of a container will determine the out-flow pressure relative to a container puncture wound, the present invention proposes a unique anti-leak protective barrier coating which, in three different embodiments, pays attention to this head-pressure consideration through possessing an increasing overall thickness from the upper to the lower potions of a liquid container wall which is to be protected by the coating.
In one preferred embodiment of the invention, the coating increases smoothly and essentially linearly in an increasing-thickness fashion from top to bottom, and in this embodiment of the invention, that thickness, at every vertical point along the wall of a protected container, bears a fixed ratio, or relationship, with respect to liquid head pressure that also varies linearly progressing downwardly in that container.
In another embodiment of the invention, the proposed coating takes the form of smoothly “flowing” progressive but non-linear thickness which might, as an illustration, follow a parabolic curve, a logarithmic curve, or other curve, etc.
In yet a third embodiment of the invention which is illustrated and described herein, the coating of this invention is staged, or stepped, in a fashion whereby, progressing downwardly along a coated wall, one engages “units” of coating which have a defined height, and within that defined height, a substantially uniform thickness. As one progresses down the wall of a container with respect to this embodiment, one engages progressively thicker units of the type just generally described.
Accordingly, the invention provides an opportunity for one to implement a protective coating of the style intended which uniquely relates its protective-coating thickness to expected stored-liquid head pressure within a protected container.
These and other features and advantages of the invention will become more fully apparent as the description which now follows is read in conjunction with the accompanying drawings.